BR112017007614B1 - PROCESS FOR THE PRODUCTION OF HIGH QUALITY 1,1,1,3-TETRACHLOROPROPAN - Google Patents

Abstract

described is a process for producing a chlorinated c3-6 alkane comprising providing a reaction mixture comprising an alkene and carbon tetrachloride in a main alkylation zone to produce chlorinated c3-6 alkane in the reaction mixture, and extracting a portion of the mixture. of reaction from the main alkylation zone, wherein: a) the concentration of the chlorinated c3-6 alkane in the reaction mixture in the main alkylation zone is maintained at a level such that the molar ratio of chlorinated c3-6 alkane:tetrachloride of carbon in the reaction mixture extracted from the alkylation zone does not exceed 95:5 when the main alkylation zone is in continuous operation; and/or b) the reaction mixture extracted from the main alkylation zone further comprises alkene and the reaction mixture is subjected to a dealkenization step in which at least about 50% by weight or more of the alkene present in the reaction mixture is extracted therefrom and at least about 50% of the extracted alkene is fed back into the reaction mixture provided in the main alkylation zone; and/or c) the reaction mixture present in the main alkylation zone and extracted from the main alkylation zone further comprises a catalyst, and the reaction mixture extracted from the main alkylation zone is subjected to an aqueous treatment step in which the mixture The reaction mixture comes into contact with an aqueous medium in an aqueous treatment zone, a biphasic mixture is formed and an organic phase comprising catalyst is extracted from the biphasic mixture.

Description

[001] The present invention relates to processes for producing high purity chlorinated C3-6 alkane compounds, such as tetrachloropropane, pentachloropropane, pentachlorobutane, and heptachlorohexane, and also to compositions comprising such compounds.

[002] Haloalkanes find use in several applications. For example, halocarbons are used extensively as coolants, blowing agents and foaming agents. During the second half of the 20th century, the use of chlorofluoroalkanes increased exponentially until the 1980s, when concerns arose about their environmental impact, specifically regarding the depletion of the ozone layer.

[003] Subsequently, fluorinated hydrocarbons such as perfluorocarbons and hydrofluorocarbons have been used in place of chlorofluoroalkanes, although more recently environmental concerns have been raised regarding the use of this class of compounds and legislation has been adopted in the United States and other countries to reduce their use.

[004] New environmentally friendly classes of halocarbons are emerging and have been investigated and, in some cases, adopted in various applications, especially as coolants in the automotive and domestic fields. Examples of such compounds include 1,1,1,2-tetrafluoroethane (R-134a), 2-chloro-3,3,3-trifluoropropene (HFO-1233xf), 1,3,3,3-tetrafluoropropene (HFO-1234ze ), 3,3,3-trifluoropropene (HFO-1243zf), and 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,2,3,3,3-pentafluoropropene (HFO-1225ye), 1- chloro-3,3,3-trifluoropropene (HFO-1233zd), 3,3,4,4,4-pentafluorobutene (HFO-1345zf), 1,1,1,4,4,4-hexafluorobutene (HFO-1336mzz) , 3,3,4,4,5,5,5-heptafluoropentene (HFO1447fz), 2,4,4,4-tetrafluorobut-1-ene (HFO-1354mfy) and 1,1,1,4,4,5 ,5,5-octafluoropentene (HFO-1438mzz)

[005] Although these compounds are, in general terms, chemically non-complex, their synthesis on an industrial scale with the required levels of purity is a challenge. Many proposed synthetic routes for such compounds increasingly use chlorinated alkanes or alkenes as starting materials or intermediates. Historically, many of the processes developed to produce such compounds have involved the addition of chlorinated alkanes to fluorinated olefins. However, such processes were found not to be acceptably effective and resulted in the production of numerous impurities. More recently developed processes are typically more direct and involve converting starting materials from chlorinated alkanes or alkenes, or from the feedstock, to fluorinated target compounds using hydrogen fluoride and transition metal catalysts, eg, chromium-based catalysts .

[006] It has been recognized that when the chlorinated feed load is obtained from a multi-step process, especially if such steps are linked and occur continuously to achieve industrially acceptable product volumes, then the need to prevent cumulative secondary reactions to starting from the generation of unacceptable impurities in each process step is very important.

[007] The purity of the chlorinated starting materials will have a substantial effect on the success and feasibility of processes (especially continuous processes) to prepare the desirable fluorinated products. The presence of some impurities will result in secondary reactions, minimizing the yield of the target compound. Removal of these impurities, even using intensive distillation steps, is also a challenge. Additionally, the presence of certain impurities will compromise the life of the catalyst, for example by poisoning the catalyst.

[008] Consequently, there is a need for efficient, reliable and highly selective processes for preparing high purity chlorinated alkanes for use in the synthesis of the fluorinated compounds mentioned above, as well as other specialized compounds. Various processes for the production of purified chlorinated compounds have been proposed in the art, for example, US6187978, US6313360, US2008/091053, US6552238, US6720466, JP2013-189402 and US2014/0171698.

[009] Despite these advances, problems can still arise through the use of chlorinated compounds obtained from the processes discussed above. In particular, the presence of impurities, especially those that are not readily separable from the compounds of interest (eg as a result of similar boiling points) or that reduce the effectiveness or operating life of catalysts used in downstream processes, can be problematic.

[0010] To minimize such disadvantages, a demand exists for high purity chlorinated alkane compounds and also for efficient, reliable and highly selective processes for the preparation of such compounds.

Thus, according to one aspect of the present invention, there is provided a process for producing a chlorinated C3-6 alkane comprising providing a reaction mixture comprising an alkene and carbon tetrachloride in a main alkylation zone to produce the C3 alkane -6 chlorinated in the reaction mixture and extracting a portion of the reaction mixture from the main alkylation zone, wherein: the concentration of the chlorinated C3-6 alkane in the reaction mixture in the main alkylation zone is maintained at a level such that the molar ratio of chlorinated C3-6 alkane:carbon tetrachloride in the reaction mixture extracted from the alkylation zone does not exceed: 95:5 where the main alkylation zone is in continuous operation, or 99:1 where the main alkylation zone is in batch operation; and/or the reaction mixture extracted from the main alkylation zone further comprises alkene and the reaction mixture is subjected to a dealkenization step in which at least about 50% by weight or more of the alkene present in the reaction mixture is extracted therefrom. and at least about 50% of the extracted alkene is fed back into the reaction mixture provided in the main alkylation zone; and/or the reaction mixture present in the main alkylation zone and extracted from the main alkylation zone further comprises a catalyst, and the reaction mixture extracted from the main alkylation zone is subjected to an aqueous treatment step in which the reaction mixture is on contact with an aqueous medium in an aqueous treatment zone, a biphasic mixture is formed and an organic phase comprising catalyst is extracted from the biphasic mixture.

[0012] The processes of the present invention are centered around a highly selective telomerization reaction that occurs, partially or completely, in the main alkylation zone. In such a reaction, carbon tetrachloride is reacted with an alkene to produce a chlorinated C3-6 alkane. Although telomerization reactions to produce chlorinated C3-6 alkanes are known in the art, one problem with such processes is the production of unwanted impurities; there remains a need for a process to produce high purity chlorinated C3-6 alkanes, in industrial volumes and ideally on a continuous basis.

[0013] It has been found, unexpectedly and advantageously, that conducting one, some or all of the steps of a) to c) as outlined above when preparing chlorinated C3-6 alkane from alkene and carbon tetrachloride improves efficiency (including reducing energy consumption) and/or minimizes the formation of impurities that would otherwise be difficult to remove from the chlorinated C3-6 alkane of interest and/or be problematic in downstream reactions where the chlorinated C3-6 alkane can be employed. Furthermore, surprisingly, the processes of the present invention balance these advantages with high selectivity and high yield.

[0014] The reaction mixture is formed by contacting alkene and carbon tetrachloride. This can occur in the main alkylation zone, for example, because both alkene and carbon tetrachloride are fed into that zone. Additionally or alternatively, the alkene may be contacted with carbon tetrachloride in a zone upstream of the main alkylation zone and then fed into the main alkylation zone.

[0015] In embodiments of the invention, the molar ratio of chlorinated C3-6 alkane:carbon tetrachloride in the reaction mixture is controlled within certain numerically defined limits. As those skilled in the art will appreciate, in such embodiments, although control over the process is characterized here in terms of the molar ratio between the carbon tetrachloride starting material and the chlorinated C3-6 alkane product, it can also be considered as control over the conversion of starting material to product - thus, a starting material:product molar ratio of 95:5 equates to a 5% conversion. The inventors have found that limiting the conversion of starting material, as outlined above, minimizes the formation of unwanted impurities. Additionally, when referring to a molar ratio of starting material:product being greater than a given value, this means a greater degree of conversion of the starting material to product, i.e., such that the proportion of the product is increased while the proportion of starting material is decreased.

[0016] For example, in embodiments of the invention, a primary alkylation zone may be employed, upstream of the main alkylation zone. The reaction mixture can be formed by feeding carbon tetrachloride and alkene into the primary alkylation zone to form the reaction mixture which is then fed into the main alkylation zone. In such an embodiment, partial conversion of carbon tetrachloride to the chlorinated C3-6 alkane of interest can occur in the primary alkylation zone such that this alkane is formed and comprised in the reaction mixture fed into the main alkylation zone, together with tetrachloride of carbon. In additional or alternative embodiments, the amount of alkene fed into the primary alkylation zone can be limited to retard the conversion of carbon tetrachloride to the chlorinated C3-6 alkane of interest in the primary alkylation zone so that the reaction mixture is fed into the zone. of the main alkylation comprises carbon tetrachloride and the chlorinated C3-6 alkane but low levels of or substantially no alkene.

[0017] The alkene and carbon tetrachloride employed in the processes of the present invention may be contacted in a zone (e.g., a primary alkylation zone or the main alkylation zone) by being fed into that zone using any technique or equipment known to those in the field. skilled in the art, for example, by means of dispersing devices such as dip tube(s), nozzle(s), ejectors, static mixing devices and/or disperser(s). In such embodiments, the alkene and/or carbon tetrachloride feed can be continuous or intermittent. The alkene supplied as a feed in the zone where the reaction mixture is formed can be in liquid and/or gaseous form. Likewise, carbon tetrachloride can be in liquid and/or gaseous form.

[0018] In embodiments of the present invention, the reaction mixture (comprising carbon tetrachloride, chlorinated C3-6 alkane product and optionally catalyst and/or unreacted alkene) present in the main alkylation zone (and/or any another zone of alkylation that may be employed) may be homogeneous, that is, in a single phase, eg a liquid or gas phase. This can be achieved even when one of the components of the reaction mixture is introduced into the system at a different stage than the other components. For example, in modalities, alkene gas can be contacted with liquid carbon tetrachloride, causing the alkene to dissolve, thus forming a homogeneous liquid-phase reaction mixture. Alternatively, the reaction mixture can be heterogeneous.

Thus, according to one aspect of the present invention, there is provided a process for producing a chlorinated C3-6 alkane comprising providing a reaction mixture comprising an alkene and carbon tetrachloride in a primary alkylation zone to produce C3-alkane 6 chlorinated in the reaction mixture, and extracting a portion of the reaction mixture from the primary alkylation zone and feeding the extracted portion of the reaction mixture into a main reaction zone and extracting a portion of the reaction mixture from the main reaction, in which the molar ratio of C-3-6 chlorinated alkane:carbon tetrachloride in the reaction mixture extracted from the main alkylation zone is greater than the molar ratio of C3-6 chlorinated alkane:carbon tetrachloride in the mixture of reaction extracted from the primary alkylation zone.

The alkene used in the processes of the present invention may be a C2-5 alkene, for example an ethene (i.e. a C2 alkene), a propene, a butene or a pentene. The alkene may or may not be halogenated, for example chlorinated and/or substituted. In arrangements where the alkene is chlorinated, it preferably comprises 1, 2, 3, 4 or 5 chlorine atoms. In embodiments of the present invention, the chloroalkene has the general formula: CHaXb=R, where a is 1 or 2, b is 0 or 1, X is halogen (e.g., chlorine) and R is substituted or unsubstituted C1-4 alkyl replaced.

[0021] Examples of alkene materials that can be employed in the processes of the present invention include ethene, vinyl chloride, propene, 2-chloropropene, 3-chloropropene, 2,3,3,3-tetrachloropropene, 1,1-dichloroethene, trichloroethene, chlorofluoroethene, 1,2-dichloroethene, 1,1-dichloro-difluoroethene, 1-chloropropene, 1-chlorobutene and/or any of the other alkenes disclosed in US5902914 and EP131561, the contents of which are incorporated herein by reference.

[0022] The carbon tetrachloride and alkene starting materials employed in the processes of the present invention may have a high degree of purity, for example, one or both of these materials may be at least about 95% pure, at least about 97% pure, at least about 99% pure, at least about 99.5% pure, at least about 99.7% pure, or at least about 99.9% pure.

[0023] In embodiments of the present invention, the carbon tetrachloride starting material comprises less than about 2000ppm, less than about 1000ppm, less than about 500ppm, less than about 200ppm, less than about 100ppm, less than about 50ppm or less than about 20ppm bromides or brominated organic compounds.

[0024] Additionally or alternatively, the carbon tetrachloride starting material may have a moisture content of about 200ppm or less, about 100ppm or less, about 50ppm or less, or about 35ppm or less.

[0025] In the processes of the present invention, carbon tetrachloride is preferably employed as a feedstock for haloalkane. However, in alternative embodiments of the present invention, haloalkane feedstocks other than carbon tetrachloride may be employed, for example, 1,1-dichloromethane, 1,1,1-trichloroethane, 1,1-dichlorofluoromethane, 1-trichlorotrifluoroethane, 1,1,2-trichlorotrifluoroethane, tetrachloroethane, pentachloroethane, hexachloroethane and/or any of the other chloroalkanes disclosed in US5902914, the contents of which are incorporated herein by reference.

[0026] The source of carbon tetrachloride may be located in the same place as the apparatus for operating the processes of the present invention. In embodiments, the source of carbon tetrachloride may be adjacent to a chlor-alkali plant with, for example, a membrane electrolysis plant, from which high purity chlorine will be available for use in the production of carbon tetrachloride. The site may also comprise facilities to produce epichlorohydrin (eg from glycerol feedstock), glycidol and/or epoxy resin, so that hydrogen chloride gas, produced as a by-product in any of the associated steps or processes be effectively used as well. Thus, for the best economic use of a chlorine-alkaline plant, an integrated plant with plants for reactions with chlorine and capture/reuse of hydrogen chloride is foreseen.

[0027] The reaction mixture can be extracted from the main alkylation zone (and/or, if employed, from the primary alkylation zone) on a continuous or intermittent basis. For the avoidance of doubt, when reference is made in the present application to the continuous extraction of material from the zones employed in the process of the present invention, it should not be given a purely literal meaning. One skilled in the art would recognize that, in such modalities, material can be removed on a substantially continuous basis while the zone in question is in operating condition and, if its objective is to establish a steady state reaction (eg, a alkylation) once the reaction mixture has reached the required steady state.

[0028] One of the advantages of the present invention is that the presence of some impurities typically observed in commercially supplied alkene (such as certain organic impurities, for example, such as alcohols, ethers, esters and aldehydes) can be tolerated and/or the impurities removed using steps of the process outlined here. This advantage is especially beneficial in arrangements where the alkene is ethene; ethylene can be derived from bioethanol, ethanol or crude oil.

[0029] A further advantage of the processes of the present invention is that i) continuous production of chlorinated alkane and ii) substantially complete utilization of the alkene starting material can be achieved without escape of the alkene to the tail gas system.

The chlorinated C3-6 alkane can be a chloropropane, a chlorobutane, a chloropentane or a chlorohexane. The chlorinated C3-6 alkane may comprise 4, 5, 6, 7, 8 or more chlorine atoms. Examples of chlorinated C3-6 alkane compounds that can be produced in high purity according to the processes of the present invention include tetrachloropropane, for example, 1,1,1,3-tetrachloropropane, tetrachlorobutane, hexachlorobutane, heptachlorobutane, octachlorobutane, pentachloropropane , pentachlorobutane, for example 1,1,1,3,3-pentachlorobutane, and heptachlorohexane.

[0031] One of the advantages of the processes of the present invention is that they can allow the production of a target chlorinated C3-6 alkane with high isomeric selectivity. Thus, in such embodiments of the invention, the chlorinated C3-6 alkane product is produced with isomer selectivity of at least about 95%, at least about 97%, at least about 98%, at least about 99%, at least about 99.5%, at least about 99.7%, at least about 99.8%, or at least about 99.9%

[0032] The alkylation reaction conducted in the processes of the present invention, to produce chlorinated C3-6 alkane, can be accelerated through the use of a catalyst. As used herein, the term catalyst is used to encompass not only the use of a unique compound or material having a catalytic effect, for example, a solid metal or a metal salt, but a catalyst system which may further comprise a catalytic material and a co-catalyst or promoter, such as a linker.

[0033] Any catalyst known to those skilled in the art finds utility in forming a chlorinated C3-6 alkane from carbon tetrachloride and alkene can be employed.

[0034] In embodiments of the invention, the catalyst is metallic. Any metal that can function as a catalyst in the alkylation reaction of the present invention can be used, including, but not limited to copper and/or iron. The metallic catalyst may be present in its solid form (for example, in the case of copper or iron, in particulate form (for example, powder or chips), wire and/or mesh or the like) and/or as a salt in which the metal can be in any oxidation state (eg cuprous salts such as cuprous chloride, cuprous bromide, cuprous cyanide, cuprous sulphate, cuprous phenyl and/or ferrous and/or ferric salts such as ferrous chloride and ferric chloride).

[0035] When metal salts are employed as catalysts in the processes of the present invention, they can be added to the alkylation zone(s) and/or form EM SITU therein. In the latter case, solid metal can be added to the alkylation zone(s) and, due to the conditions therein, the salt can be formed. For example, if solid iron is added to a chlorination reaction mixture, the chlorine present can combine with elemental iron to form ferric or ferrous chloride IN SITU. When metal salts are formed IN SITU, it may still be desirable to maintain a predetermined level of elemental metal catalyst in the reaction mixture (eg, an excess of elemental metal compared to the level of metal salt(s) ) and/or binder) and thus additional elemental metal catalyst may be added as the reaction proceeds, either continuously or intermittently.

[0036] As mentioned above, in embodiments of the present invention, the catalyst may also comprise a binder, preferably an organic binder, which may form a complex with the metal catalyst. Suitable binders include amines, nitrites, amides, phosphates and phosphites. In embodiments of the invention, the binder used is an alkyl phosphate, such as trimethyl phosphate, triethyl phosphate, tributyl phosphate and triphenyl phosphate.

[0037] Additional metal catalysts and binders are known to those skilled in the art and are described in the prior art, for example US 6187978, the contents of which are incorporated by reference.

The components of the catalyst system, when used, can be fed into the alkylation zone(s) (e.g. the main alkylation zone and/or, if used, the primary alkylation zone) continuously or intermittently. Additionally or alternatively, they may be introduced into the alkylation zone(s) (for example, the main alkylation zone and/or, if used, the primary alkylation zone) prior to and/or during the start of the reaction. of alkylation.

[0039] Additionally or alternatively, the catalyst (or catalyst components, eg the binder) may be fed into the alkylation zone(s) (eg the main alkylation zone or, if used, the primary alkylation zone ) together with other components of the reaction mixture, for example, in a feed of carbon tetrachloride and/or ethene.

[0040] In embodiments of the invention, wherein the catalyst comprises a metallic catalyst and a promoter as a binder, the molar ratio of promoter:metal catalyst in the reaction mixture present in the main alkylation zone and/or, if used, the zone of primary alkylation is maintained at a ratio greater than 1:1, more preferably at a ratio greater than 2:1, 5:1 or 10:1.

[0041] When solid metal catalyst is added to the reaction mixture, it can be added to the primary alkylation zone, if used, and/or the main alkylation zone. In embodiments of the invention, solid metal catalyst is added to the primary alkylation zone, if used, and/or the main alkylation zone in amounts to maintain a level of about 0.1 to 4%, about 0.5 to 3% or about 1 to 2% by weight of the reaction mixture.

[0042] Additionally or alternatively, when metal catalysts are employed, they are added to establish a dissolved metal content of about 0.1%, about 0.15%, or about 0.2% to about 1.0 , about 0.5 or about 0.3% by weight of the reaction mixture.

[0043] In embodiments of the invention, in which the catalyst system employed comprises a metallic catalyst and promoter, the metallic catalyst and promoter may be added to the reaction mixture simultaneously and/or in the same part of the apparatus, for example, in the zone of primary alkylation (if used) and or in the main alkylation zone.

[0044] Alternatively, the metallic catalyst and promoter can be added at different locations in the apparatus, either sequentially or separately. For example, solid metal catalyst can be added to the primary alkylation zone with promoter being fed into that zone from a recycle loop to which an additional fresh promoter can also be added.

[0045] In embodiments of the invention, the primary and/or main alkylation zones are operated under atmospheric or superatmospheric pressure, i.e., at a pressure greater than about 100kPa, greater than about 200kPa, greater than about 300kPa, greater than about 400kPa, greater than about 500kPa, greater than about 600kPa, greater than about 700kPa, or greater than about 800kPa. Typically, the pressure in the primary and/or main alkylation zones will be equal to or less than about 2000kPa, about 1700kPa, about 1500kPa, about 1300kPa, about 1200kPa or about 1000kPa.

[0046] Additionally or alternatively, in embodiments of the invention, the primary and/or main alkylation zones are operated at elevated temperatures, i.e., temperatures equal to or greater than about 30°C, about 40°C, about 50°C, about 60°C, about 70°C, about 80°C, about 90°C, or about 100°C. Typically, the primary and/or main alkylation zones will be operated at temperatures equal to or less than about 200°C, about 180°C, about 160°C, about 140°C, about 130°C, about 120°C, or about 115°C.

[0047] The use of temperatures and pressures within these ranges combined with the other characteristics of the processes of the present invention have been found, advantageously, to maximize the yields and/or selectivity of the chlorinated C3-6 alkane of interest, while minimizing the formation of problematic by-products.

[0048] In processes of the invention, a plurality of alkylation zones can be employed. Any number of alkylation zones can be employed, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 or more. In embodiments where a plurality of primary and/or main alkylation zones are employed, any number (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 or more) of primary and/or primary alkylation zones.

[0049] For the avoidance of doubt, when referring to the properties of an alkylation zone (primary and/or main), for example, its operating conditions, its mode of operation, its properties, etc., insofar as the embodiments of the present invention are referred to, which comprise a plurality of zones of primary and/or main alkylation, one, some or all of these zones may exhibit the property(s) in question. For example, if, for brevity, reference is made to a main alkylation zone having a specified operating temperature, then, as modalities including a plurality of main alkylation zones are referred to, it should be considered as a reference to that one, some or all of these main alkylation zones are operated at the specified temperature.

[0050] In arrangements where a plurality of primary and/or main alkylation zones are employed, such alkylation zones may be operated in parallel and/or in series.

[0051] In arrangements where primary and main alkylation zones are employed, the alkylation reaction between alkene and carbon tetrachloride can be controlled to prevent it from proceeding beyond a certain degree of completion in the primary alkylation zone, for example, from so that the molar ratio of chlorinated C3-6 alkane:carbon tetrachloride in the reaction mixture extracted from the primary alkylation zone and/or fed into the main alkylation zone does not exceed 85:15, 90:10, 93:7 or 95:5, although this is not essential. Additionally or alternatively, the reaction can be allowed to proceed at a relatively advanced completion stage, such that the molar ratio of chlorinated C3-6 alkane:carbon tetrachloride in the reaction mixture extracted from the primary alkylation zone and/or fed into the zone of main alkylation is greater than 50:50, 60:40, 70:30, 75:25 or 80:20.

[0052] Controlling the progress of the alkylation reaction in the primary alkylation zone can be achieved through the use of reaction conditions that do not favor the total conversion of carbon tetrachloride to 1,1,1,3-tetrachloropropane. Additionally, or alternatively, controlling the progress of the alkylation reaction in the primary alkylation zones can be achieved by carefully selecting the residence time of the reaction mixture in the primary alkylation zones, for example, about 20 to 300 minutes, about 40 to 250 minutes, about 60 to about 200 minutes, or about 90 to about 180 minutes. In embodiments of the invention, the molar ratio can be controlled by limiting the amount of alkene fed into the primary and/or main alkylation zones. For example, the molar ratio of carbon tetrachloride:alkene fed into the primary and/or main alkylation zones can range from about 50:50 to about 55:45, about 60:40, about 65:35, about about 70:30, about 75:25, about 80:20, about 85:15, or about 90:10.

[0053] In embodiments where primary and main alkylation zones are employed, the larger volume of the chlorinated C3-6 alkane can be produced in the primary alkylation zone. In such embodiments, the proportion of C3-6 alkane produced in the main reaction zone can be significantly lower, for example, so that the molar ratio of chlorinated C3-6 alkane:carbon tetrachloride in the reaction mixture is increased by 1 to 10, 2 to 8 or 3 to 5.

[0054] For example, if the molar ratio of chlorinated C3-6 alkane:carbon tetrachloride in the reaction mixture extracted from the primary alkylation zone and fed into the main alkylation zone is 90:10, this molar ratio can be increased by 2 , 3 or 5 in the main alkylation zone so that the molar ratio of chlorinated C3-6 alkane:carbon tetrachloride present in the mixture extracted from the main alkylation zone can be 92:8, 93:7 or 95:5.

[0055] However, the feasibility of the processes of the present invention is not dependent on most of the conversion of carbon tetrachloride to the chlorinated C3-6 alkane of interest taking place in the primary reaction zone. Thus, in alternative embodiments, the degree of conversion of carbon tetrachloride to the chlorinated C3-6 alkane of interest can be balanced between the primary and main alkylation zones or can be greater in the main alkylation zone than in the primary alkylation zone.

[0056] The reaction mixture can then be withdrawn from the primary alkylation zone (continuously or intermittently) and fed into the main alkylation zone where a proportion of the remaining carbon tetrachloride present in the reaction mixture is converted to the C3-alkane 6 chlorinated of interest. In such embodiments, any unreacted alkene starting material present in the reaction mixture can advantageously be totally (or at least almost totally) utilized.

[0057] In the processes of the invention, when employed, the primary and main alkylation zones can be operated under different conditions. The main alkylation zone may be operated at a pressure greater than that of the primary alkylation zone(s), for example, at a pressure that is at least about 10kPa greater, 20kPa greater, about 50kPa greater, about 100kPa bigger, about 150kPa bigger, about 200kPa bigger about 300kPa or about 500kPa bigger.

[0058] In embodiments of the invention, alkene cannot be fed into the main alkylation zone; the only source of alkene for those zone(s) may be in the reaction mixture fed into the main alkylation zone.

[0059] Additionally, in embodiments where the alkylation reaction between carbon tetrachloride and alkene is catalyzed by a metallic catalyst (optionally including a binder), metallic catalyst and/or binder cannot be fed into the main alkylation zone. In such embodiments, the only source of catalyst can be the reaction mixture fed into the main alkylation zone. Additionally or alternatively, the main alkylation zone may be provided with a bed of catalyst.

[0060] In the processes of the present invention, in which primary and primary alkylation zones are employed, and solid metal catalyst is present in the reaction mixture in the primary alkylation zone (e.g., being added directly to it), when mixing The reaction mixture is extracted from the primary alkylation zone in order to be fed into the main alkylation zone, the extraction of the reaction mixture from the primary alkylation zone can be carried out so that very little, if any, solid metal catalyst is present in the reaction mixture, for example, less than about 5mg, about 2mg, about 1mg, about 0.5mg, about 0.2mg, about 0.1mg of solid metal catalyst per liter of mixture of reaction.

[0061] This can be achieved through the use of any technique and/or equipment known to those of skill in the art, for example, a tube extending into the primary alkylation zone(s) at an appropriate location, being equipped with a filtration mesh and/or having an appropriate diameter.

[0062] When employed, the primary and main alkylation zones can be in the same reactor or in different ones, which can be of the same type or different types of reactors. Furthermore, in embodiments where a plurality of primary alkylation zones are employed, these can be in the same or different reactors. Also, in embodiments where a plurality of main alkylation zones are employed, these can be in the same or different reactors.

[0063] Any type of reactor or reactors known to those skilled in the art can be employed in the processes of the present invention. Specific examples of reactors that can be used to provide alkylation zones are column reactors (eg gas-liquid column reactors), tubular reactors, bubbling column reactions, plug flow reactors (eg tubular flow reactors buffer) and stirred tank reactors (eg continuously stirred tank reactors).

[0064] Arrangements where the primary alkylation zone is present in a continuously stirred tank reactor (CSTR) and the main alkylation zone is present in a plug flow reactor have given advantageous results.

[0065] An advantage of the process of the present invention is that desirable results are obtained if the alkylation zones (e.g. the primary alkylation zone and/or the main alkylation zone) are operated in a continuous process (steady state) or in batch. The terms "continuous process" and "batch process" will be understood by those skilled in the art.

[0066] In embodiments, the primary alkylation zone, when employed, is operated in a continuous or batch process. Additionally or alternatively, the second alkylation zone(s), when employed, is(are) operated in a continuous or batch process.

[0067] In the processes of the present invention, the concentration of chlorinated C3-6 alkane in the reaction mixture in the main alkylation zone is maintained at a level such that the molar ratio of chlorinated C3-6 alkane:carbon tetrachloride in the reaction mixture extracted from the main alkylation zone does not exceed: i) 95:5 when the main alkylation zone is in continuous operation, or ii) 99:1 when the main alkylation zone is in batch operation.

[0068] In certain embodiments of the invention, where the main alkylation zone is in continuous operation, the chlorinated C3-6 alkane content can be controlled so that the ratio of this compound: carbon tetrachloride in the reaction mixture extracted from the zone of main alkylation does not exceed about 94:6, about 92:8, or about 90:10

[0069] In alternative embodiments of the invention, where the main alkylation zone is in batch operation, the chlorinated C3-6 alkane content can be controlled so that the ratio of this compound: carbon tetrachloride in the reaction mixture extracted from the the main alkylation zone does not exceed about 97:3, about 95:5, or about 90:10.

[0070] Regardless of whether the main alkylation zone is in a continuous or batch process, the content of chlorinated C3-6 alkane can be controlled so that the ratio of this compound: carbon tetrachloride in the reaction mixture extracted from the zone major alkylation is equal to or greater than about 70:30, about 80:20, about 85:15, or about 90:10.

[0071] It has been surprisingly found that by controlling the degree of conversion of the carbon tetrachloride to the chlorinated C3-6 alkane of interest and preventing the reaction from proceeding to completion, the formation of impurities is advantageously reduced. For example, in embodiments where the alkene feed load employed in the processes of the present invention is ethene, the production of unwanted by-products such as pentanes (which would otherwise be formed) is minimized.

[0072] Thus, in embodiments of the invention, the reaction mixture extracted from the main reaction zone comprises series reaction products, that is, compounds comprising a greater number of carbon atoms than the chlorinated C3-6 alkane product, less than about 5%, less than about 2%, less than about 1%, less than about 0.5%, less than about 0.2%, less than about 0.1%, less than about 0.05% or less than about 0.02%.

[0073] Controlling the chlorinated C3-6 alkane content can be achieved by slowing the progress of the alkylation process and/or introducing additional carbon tetrachloride into the main alkylation zone.

[0074] In embodiments where the chlorinated C3-6 alkane content is controlled by slowing the alkylation process, this can be achieved through the use of reaction conditions that do not favor the total conversion of carbon tetrachloride to 1,1,1 ,3-tetrachloropropane. For example, this can be achieved by exposing the reaction mixture, or at least a portion thereof, to conditions that slow down or stop the progress of the alkylation reaction. In such embodiments, the pressure to which the reaction mixture is exposed in the alkylation zones (e.g., the main alkylation zone(s) when employed) can be significantly reduced, e.g. minus about 500kPa, for at least about 700kPa, for at least about 1000kPa.

[0075] Additionally or alternatively, the pressure to which the reaction mixture is exposed can be reduced to atmospheric or subatmospheric pressure. Pressure reduction can occur in one or more alkylation zones (eg one, some or all of the main alkylation zones, if used). Additionally or alternatively, the reduction in pressure may occur after extraction of the reaction mixture from the alkylation zone(s).

[0076] Additionally or alternatively, in embodiments where the chlorinated C3-6 alkane content is controlled by slowing down the alkylation process, this can be achieved by limiting the level of alkene present in the reaction mixture.

[0077] In embodiments of the invention, control of the progress of the alkylation reaction in the alkylation zone(s) can be achieved by carefully selecting the residence time of the reaction mixture in the zone(s) of alkylation. For example, in embodiments where one or more major alkylation zones are employed, the residence time of the reaction mixture in those zone(s) can be, for example, about 1 to 120 minutes, about 5 to 100 minutes, about 15 to about 60 minutes or about 20 to about 40 minutes.

[0078] In embodiments where the chlorinated C3-6 alkane content is controlled by slowing down the alkylation process, this can additionally or alternatively be achieved by lowering the operating temperature of the main alkylation zone, for example, by about 5°C or more, about 10°C or more, about 20°C or more, about 50°C or more, or about 100°C or more. Additionally or alternatively, the operating temperature of the main conversion zone can be reduced to about 20°C, about 10°C, or about 0°C.

[0079] Additionally or alternatively, the alkylation process can be slowed down by limiting the amount of catalyst present in the reaction mixture, or removing the catalyst bed (if present) from the main alkylation zone.

[0080] The agitation or stirring rate of the main alkylation zone can also be reduced to slow down the alkylation process.

[0081] As mentioned above, the reaction mixture extracted from the main alkylation zone comprises carbon tetrachloride and chlorinated C3-6 alkane. However, in embodiments of the invention, depending on the conditions and equipment employed, the reaction mixture extracted from the main alkylation zone may additionally comprise unreacted alkene starting material, catalyst and/or impurities (e.g., alkane impurities chlorinated, chlorinated alkene impurities and/or oxygenated organic compounds).

[0082] Since the presence of unreacted alkene alongside chlorinated C3-6 alkane can be problematic, particularly for downstream processes employing chlorinated C3-6 alkane, in embodiments of the invention, the reaction mixture extracted from the alkylation zone main is subjected to a desalting step in which at least about 50% or more by weight of the alkene present in the reaction mixture is extracted therefrom and at least about 50% of the extracted alkene is fed back to the reaction mixture provided in the main alkylation zone.

[0083] Such modalities are particularly advantageous since they allow substantial, if not total, use of the alkene feed employed in the processes of the present invention.

[0084] In embodiments of the invention, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 97% or at least about 99% of the alkene present in the reaction mixture extracted from the main alkylation zone is removed during the desalting step.

[0085] Removal of unreacted alkene from the reaction mixture can be achieved using any technique known to those skilled in the art. In embodiments of the invention, extraction of alkene from the reaction mixture can be achieved using distillation techniques that result in an alkene-rich stream being obtained, for example, by flash evaporation, which can be conveniently implemented in modalities where the alkene's boiling point is substantially lower than the boiling point of other compounds present in the reaction mixture, as is the case with ethene (-103.7°C) versus carbon tetrachloride (76.6°C) and 1 ,1,1,3-tetrachloropropane (159°C).

[0086] The desalting of the reaction mixture can be selective. In other words, the alkene is selectively extracted, without substantial removal of other compounds from the reaction mixture. In such embodiments, the alkene extracted from the reaction mixture can comprise less than about 10%, less than about 5%, less than about 2%, or less than about 1% of compounds other than the starting material. alkene starting.

[0087] Distillation of the reaction mixture can be achieved by any techniques or using any equipment known to those skilled in the art. For example, conventional distillation apparatus can be employed (eg a distillation column). Additionally or alternatively, in embodiments of the invention, where the pressure in the main alkylation zone from which the reaction mixture is extracted is superatmospheric, evaporation of the alkene from the reaction mixture can be achieved by holding the reaction mixture at a superatmospheric pressure after extracting the main alkylation zone and feeding it into an evaporation zone where evaporation of the alkene from the reaction mixture takes place.

[0088] In embodiments of the invention, evaporation of alkene from the reaction mixture in the evaporation zone can be achieved by depressurization, for example, by significantly reducing the pressure that the reaction mixture is under, for example, by at least about 500kPa, at least about 700kPa, at least about 1000kPa, and/or atmospheric or subatmospheric pressure. Conveniently, in embodiments where depressurization is used partially or fully to decelerate or stop the conversion of carbon tetrachloride to the chlorinated C3-6 alkane of interest, and also to separate the alkene from the reaction mixture, these objectives can be achieved. simultaneously in a single depressurization step.

[0089] The evaporation zone can be in any apparatus in which the evaporation of the alkene present in the reaction mixture can be achieved, for example, an instant evaporation apparatus, such as a FLASH drum.

[0090] The alkene distilled from the reaction mixture, for example by instantaneous evaporation, is preferably extracted from the distillation apparatus in liquid or gaseous form.

[0091] In processes of the present invention, at least about 50%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 97% or at least about 99% by weight of the alkene extracted from the evaporation zone is fed back (i.e. recycled) to the primary and/or main alkylation zone.

[0092] For the avoidance of doubt, in embodiments of the invention, the distilled alkene, if in gaseous form, may or may not be converted back into a liquid, before being fed to the reaction mixture provided in the main alkylation zone. For example, the conversion of gaseous alkene to liquid alkene can be achieved by being passed through a condenser and/or trapped in a stream of liquid carbon tetrachloride (preferably cooled), which can then be fed into the alkylation zone(s). Alkene gas can be trapped in a liquid stream of carbon tetrachloride using any techniques or equipment known to those skilled in the art, for example, an absorption column. This arrangement is advantageous as it aids the full industrial utilization of the compounds employed in the alkylation process.

[0093] As mentioned above, in embodiments of the invention, a catalyst, for example, a catalyst system comprising solid metal catalyst and/or metal salt and a promoter, such as a binder, can be used in the reaction mixture present in the ) alkylation zone(s). In such embodiments, reaction mixture extracted from the alkylation zone(s) can comprise catalyst. Since the presence of catalyst can be problematic in downstream reactions employing chlorinated C3-6 alkane, it may be preferable to remove the catalyst from the reaction mixture.

[0094] Additionally, for catalyst systems in which expensive catalysts and/or promoters, such as the above mentioned alkyl phosphate and alkyl phosphite binders, are employed, recovery of reusable catalyst systems and/or components thereof is also preferable to minimize amounts of fresh catalyst that must be used, thus reducing operating cost.

[0095] Although the challenge of removing catalysts of the type employed in the processes of the present invention from reaction mixtures has been addressed in the past, the techniques and conditions employed to accomplish this (typically involving distillation using aggressive conditions) can be detrimental to catalyst systems and reduce their catalytic capacity. This is especially the case where the catalyst system is temperature sensitive, as is the case for systems including certain organic binders as promoters, such as alkyl phosphates and alkyl phosphites.

[0096] Thus, in embodiments of the present invention, the reaction mixture extracted from the main alkylation zone is subjected to an aqueous treatment step in which the reaction mixture is contacted with an aqueous medium in an aqueous treatment zone, a mixture biphasic is formed and an organic mixture comprising catalyst is extracted from the biphasic mixture.

[0097] In embodiments of the invention, wherein the reaction mixture is subjected to an aqueous treatment step, the reaction mixture may comprise unreacted carbon tetrachloride and chlorinated C3-6 alkane product. Additionally, the reaction mixture may comprise catalyst (for example, a complex of the metal catalyst and catalyst binder, or the free catalyst binder) and/or unreacted alkene starting material.

[0098] Through the use of the aqueous treatment step, the harmful conditions described in the prior art (e.g., high temperature, high catalyst concentration and/or the presence of iron compounds in anhydrous form) can be avoided, meaning that the recovered catalyst and/or components thereof (eg the binder or promoter) can be reused (eg can be recycled back to the reaction mixture supplied in the alkylation zone(s)) without any substantial loss in catalytic capacity. In embodiments of the invention, removal of vapor from the treated aqueous biphasic mixture is preferred, as boiler temperatures in excess of 100°C can be avoided and atmospheric pressure can be employed.

[0099] Another advantage of the aqueous treatment step is that it results in the removal of impurities from the reaction mixture, for example, oxygenated organics, if present. More specifically, when processes involve alkenes as precursors, for example, ethene, propene, 1-butene, 2-butene, 1-hexene, 3-hexene, 1-phenyl-3-hexene, butadiene, vinyl halides and the like, compounds oxygenated organics (eg, alkanols, alkanoyls, and chlorinated analogues of these oxygenated compounds) can potentially be formed. Advantageously, the levels of such materials in the reaction mixture are significantly reduced to acceptable levels, if not eliminated, by the aqueous treatment step.

[00100] In embodiments of the invention, in which an aqueous treatment step is carried out, the reaction mixture provided in the aqueous treatment zone may comprise the chlorinated C3-6 alkane of interest (e.g., in amounts of about 50% or major), catalyst and optionally carbon tetrachloride and/or impurities, for example organic oxygen compounds, chlorinated alkane compounds (other than the chlorinated C3-6 alkane of interest) and or chlorinated alkene compounds.

[00101] This catalytic recovery process involves the reaction mixture being subjected to an aqueous treatment step in which the reaction mixture is contacted with an aqueous medium in an aqueous treatment zone. In embodiments, the aqueous medium is water (as a liquid and/or vapor). Additionally, the aqueous medium may additionally comprise other compounds, such as acids. Inorganic acids such as hydrochloric acid, sulfuric acid and/or phosphoric acid can be used.

[00102] When the aqueous medium fed into the aqueous treatment zone is partially or fully in liquid form, a biphasic mixture will be formed in the liquid aqueous medium contacting the reaction mixture.

[00103] Alternatively, when the aqueous medium is in gaseous form, eg steam, a two-phase mixture may not be formed immediately, but only as the gaseous aqueous medium condenses. The apparatus employed in the aqueous treatment step may be configured so that condensation of the aqueous medium to form the biphasic mixture takes place within and/or remote from the aqueous treatment zone.

[00104] In embodiments of the invention, the chlorinated C3-6 alkane product can be extracted from the mixture formed in the aqueous treatment zone. Most (e.g., at least about 50%, at least about 60%, at least about 70%, at least about 80%, or at least about 90%) of the chlorinated C3-6 alkane present in the The reaction mixture fed into the aqueous treatment zone can be extracted from the mixture formed in the aqueous treatment zone using any techniques or equipment known to those skilled in the art.

[00105] In embodiments of the invention, distillation is used to extract the chlorinated C3-6 alkane product from the mixture formed in the aqueous treatment zone. Distillation can result in obtaining a stream rich in chlorinated C3-6 alkane.

[00106] As used throughout the specification, the term "a stream rich in" a specific compound (or corresponding expression) is used to mean that the stream comprises at least about 90%, about 95%, about 97 %, about 98% or about 99% of the specific compound. Furthermore, the term "stream" is not to be interpreted narrowly, but encompasses compositions (including fractions) extracted from a mixture via any means.

[00107] For example, the C3-6 alkane can be distilled, for example, from a gas mixture comprising this alkane and water vapor. Chlorinated C3-6 alkane can be distilled in a stream rich in chlorinated C3-6 alkane. In embodiments of the invention, where the aqueous medium is partially or wholly in liquid form, distillation of the chlorinated C3-6 alkane can be achieved by boiling the present mixture to evaporate the chlorinated C3-6 alkane and produce the C3-6 alkane mixture. chlorinated gas/water vapor from which chlorinated C3-6 alkane can be distilled, for example, using steam distillation techniques.

[00108] Additionally or alternatively, when the aqueous medium is provided partially or wholly in gaseous form, this evaporates the chlorinated C-3-6 alkane to form the gas mixture comprising such alkane and water vapor which can then optionally be subjected to distillation to remove C3-6 alkane, eg steam distillation. Chlorinated C3-6 alkane can be obtained in a stream rich in this compound.

[00109] In embodiments, in which the chlorinated C3-6 alkane is distilled from a gaseous mixture of chlorinated C3-6 alkane and water vapor, the distillation apparatus can be coupled to the aqueous treatment zone so that the chlorinated alkane gas/water vapor mixture can pass directly from the aqueous treatment zone to this apparatus. Alternatively, the distillation apparatus may be located remotely from the aqueous treatment zone, so that the gas mixture is first extracted from the aqueous treatment zone and then transported to the distillation apparatus. In either arrangement, chlorinated C3-6 alkane can be obtained in a stream rich in this compound.

[00110] In alternative embodiments, where the aqueous medium and reaction mixture are in liquid form, the chlorinated C3-6 alkane can be extracted from that liquid mixture using conventional distillation techniques known to those skilled in the art. Chlorinated C3-6 alkane can be obtained in a stream rich in this compound.

[00111] The biphasic mixture can be formed within the aqueous treatment zone or remotely from it. The biphasic mixture comprises an aqueous phase (as a result of the aqueous medium added to the aqueous treatment zone) and an organic phase (comprising chlorinated C3-6 alkane, optionally unreacted carbon tetrachloride, and mainly catalyst).

[00112] To maximize the volume of the organic phase and thus facilitate the extraction of this phase from the biphasic mixture, a haloalkane extracting agent (for example, carbon tetrachloride and/or chlorinated C3-6 alkane of interest) can be added to the biphasic mixture (for example, by being continuously or intermittently fed into the aqueous treatment zone) using techniques and equipment known to those skilled in the art.

[00113] The organic phase can be extracted from the biphasic residue using any technique known to those skilled in the art, eg decantation. For example, organic phase extraction can be carried out by sequential phase extraction from the aqueous treatment zone or the vessel in which it is contained. Alternatively, the biphasic mixture can be extracted from the aqueous treatment zone and subjected to a phase separation step remote from the aqueous treatment zone.

[00114] In embodiments of the invention, the biphasic mixture and/or the extracted organic phase can be filtered. In embodiments, this will result in obtaining a filter cake which can optionally be employed in whole or in part as an iron source.

[00115] Extraction of the chlorinated C3-6 alkane product from the mixture formed during the aqueous treatment step can be carried out before extracting the organic phase therefrom and/or after the organic phase is extracted from this mixture. Some exemplary embodiments in which the chlorinated C3-6 alkane product is extracted from the mixture formed during the aqueous treatment step are outlined above.

[00116] As another example, the biphasic mixture can be heated to form a gas mixture from which chlorinated C3-6 alkane product can be extracted (optionally as a stream rich in chlorinated C3-6 alkane), e.g. distillation. The organic phase, having a reduced proportion of chlorinated C3-6 alkane, can then be extracted from the biphasic mixture.

[00117] Additionally or alternatively, the organic phase can be extracted from the biphasic mixture as discussed above. Chlorinated C3-6 alkane can then be extracted (optionally as a chlorinated C3-6 alkane rich stream) from this stage, for example, via distillation. In such embodiments, where the organic phase comprises catalyst, the distillation conditions selected to extract the chlorinated C3-6 alkane are mild so as to minimize deactivation of the catalyst system, for example, at a temperature of about 100°C or less, about 95°C or less, about 90°C or less, about 85°C or less, or about 80°C or less, and/or at a pressure of about 1 to 10kPa. Lower pressures can additionally or alternatively be used.

The extracted organic phase may comprise carbon tetrachloride and/or chlorinated C3-6 alkane product. Additionally, the reaction mixture may comprise catalyst (e.g. the complex of a metal catalyst and catalyst binder or free binder) and/or unreacted alkene starting material. Since a stream rich in chlorinated C3-6 alkane has been extracted from the mixture formed in the aqueous treatment step (either directly or after extracting the organic phase from it), the chlorinated C-3-6 alkane content of this phase will be lower than in the reaction mixture.

[00119] In provisions of the invention, especially those in which the organic phase comprises carbon tetrachloride and/or catalyst, the organic phase can be fed back to the alkylation zone(s), for example, in liquid form . In such arrangements, the alkene starting material (e.g., in gaseous form) can be trapped in the organic phase stream being fed into the alkylation zone(s).

[00120] In embodiments of the invention, one or more distillation steps, in addition to those discussed above, can be carried out at any point in the process, optionally to obtain a stream rich in specific products. For example, before an aqueous treatment step, if carried out, the reaction mixture can be subjected to a distillation step. In embodiments where the reaction mixture contains a temperature-sensitive catalyst system, for example one including an organic binder as a promoter, the distillation step is typically conducted under conditions to avoid catalyst deactivation, for example, at a temperature of about 100°C or less, about 95°C or less, about 90°C or less, about 85°C or less, or about 80°C or less, and/or at a pressure of about 1 at 10kPa. Lower pressures can additionally or alternatively be used.

[00121] Additionally, it was found that the inactivation of temperature-sensitive catalyst systems can be avoided by not super-distilling the reaction mixture. Thus, in embodiments of the invention, where the reaction mixture containing a catalyst system is distilled, distillation cannot be allowed to result in the volume of process liquid in the distillation apparatus being reduced so that the concentration of the catalyst system in that liquid of process, is about 2X, about 5X, or about 10X greater than the level of that catalyst system present in the reaction mixture provided in the main alkylation zone.

[00122] A distillation step conducted before the aqueous treatment step (if performed) can be performed using techniques and equipment known to those skilled in the art, for example, a distillation boiler (batch or continuous) in communication with a distillation column vacuum. In such an embodiment, the reaction mixture subjected to distillation may comprise more than about 50% by weight of the chlorinated C3-6 alkane of interest, catalyst and optionally carbon tetrachloride and/or impurities, e.g., organic oxygen compounds , chlorinated alkane compounds (other than the C 3-6 chlorinated alkane of interest) and or chlorinated alkene compounds.

[00123] The distillation step typically results in the removal of chlorinated alkane distillate stream(s), for example stream(s) of (and optionally rich in) unreacted carbon tetrachloride, the C3-6 alkane of interest and /or chlorinated organic impurities (i.e., chlorinated organic compounds other than the C3-6 alkane of interest and carbon tetrachloride) from the reaction mixture. Carbon tetrachloride can be recycled back to the alkylation zone(s). The residue from such a step, which typically comprises amounts of chlorinated C3-6 alkane, carbon tetrachloride and/or catalyst, may be subjected to further treatment steps, for example an aqueous treatment step and/or other distillation steps.

[00124] In embodiments of the invention, where the reaction mixture is subjected to a distillation step before the aqueous treatment step (if performed), at least about 30%, at least about 50%, at least about 60 % or at least about 70% to at most about 95%, at most about 90%, at most about 85% or at most about 80% by weight of the chlorinated C3-6 alkane of interest is removed of the reaction mixture in this distillation step.

[00125] One or more distillation steps may be additionally or alternatively performed after the aqueous treatment step (if performed). For example, the chlorinated C3-6 alkane extracted from the reaction mixture fed to the aqueous treatment zone may be present in the form of a mixture comprising, as a main constituent, the chlorinated C3-6 alkane, a haloalkane extracting agent, as well as As chlorinated organic impurities (ie chlorinated organic compounds other than the C3-6 alkane of interest and carbon tetrachloride). This mixture can be subjected to one or more distillation steps to remove chlorinated organic impurities, to obtain a stream rich in chlorinated C3-6 alkane and/or to remove the haloalkane extracting agent. Again, any equipment or conditions known to those skilled in the art can be employed in such a distillation step, for example, a distillation boiler (batch or continuous) in communication with a vacuum distillation column.

[00126] In such a distillation step, the chlorinated C3-6 alkane extracted from the reaction mixture provided in the aqueous treatment zone can be subjected to distillation to separate the chlorinated C3-6 alkane of interest from the chloroalkane impurities. For example, in embodiments where the chlorinated C3-6 alkane of interest is 1,1,1,3-tetrachloropropane, a distillation step to purify the chlorinated C3-6 alkane extracted from the reaction mixture provided in the aqueous treatment zone was found to be particularly effective in removing chloropentane/chloropentene impurities.

[00127] Chlorinated organic impurities separated from mixtures comprising the chlorinated C3-6 alkane of interest in distillation steps carried out at any stage stage in processes of the present invention can be recovered and reused in the production of carbon tetrachloride. This can be achieved by subjecting the chlorinated organic impurities to a high temperature chlorinolysis process. In such a process, all chlorinated organic compounds present are mainly reprocessed back into pure tetrachloromethane in high yields. Thus, the use of a chlorinolysis step in the processes of the present invention is usable to maximize overall synthesis yield and target chloroalkane purity, while minimizing waste production.

[00128] Without taking into account the identity of the chlorinated C3-6 alkane of interest, in embodiments of the invention, a "heavy" residue can be formed in a distillation boiler, if used, after the aqueous treatment step. The "heavy" residue is typically extracted from the system and treated, for example, in a high temperature chlorinolysis process preferably leading to the production of chloromethanes.

[00129] The processes of the present invention are particularly advantageous, as they allow highly pure chlorinated alkanes to be produced, through the use of simple and straightforward techniques and equipment well known to those skilled in the art.

[00130] As can be seen from the description presented here, the inventive processes of the present invention can be operated in an integrated process in a fully continuous mode, optionally in combination with other processes. The process steps of the present invention can employ starting compounds which are converted to highly pure intermediates which are themselves further processed to the required target chlorinated compounds. These compounds have the required purity to be employed as feedstocks in a range of downstream processes, eg hydrofluorination conversions.

[00131] The processes of the present invention allow product purity levels to be controlled to achieve high purity levels of the compounds at each step. The processes advantageously balance high yields, high selectivity and high efficiency, which is particularly challenging, especially in continuous processes. The processes of the present invention allow high purity chloroalkane compounds to be economically produced on an industrial scale, the compounds having very low levels of a range of impurities, such as haloalkanes or haloalkenes, (particularly those that are isomeric to the compound of interest and /or which have a higher molecular weight, such as the products of series reactions), and/or oxygenated and/or brominated analogues, as well as water, and metallic species.

[00132] In embodiments of the invention, the processes of the invention can be used to produce high purity chlorinated alkane compositions comprising: about 99.0% or more, about 99.5% or more, about 99.7 % or more, about 99.8% or more, or about 99.9% or more chlorinated alkane, less than about 2000ppm, less than about 1000ppm, less than about 500ppm, less than about of 200ppm or less than about 100ppm chlorinated alkane impurities (i.e., chlorinated alkane compounds other than the chlorinated C3-6 alkane of interest), less than about 2000ppm, less than about 1000ppm, less than about 500ppm, less than about 200ppm or less than about 100ppm chlorinated alkene compounds, less than about 2000ppm, less than about 1000ppm, less than about 500ppm, less than about 200ppm or less than about 100ppm oxygenated organic compounds, less than about 500ppm, less than about 200ppm, less than q u about 100ppm, less than about 50ppm, or less than about 20ppm metal catalyst, less than about 500ppm, less than about 200ppm, less than about 100ppm, less than about 50ppm, or less than about 20ppm catalyst promoter, less than about 2000ppm, less than about 1000ppm, less than about 500ppm, less than about 200ppm or less than about 100ppm bromides or organic compounds brominated, and/or less than about 1000ppm, less than about 500ppm, less than about 200ppm, less than about 100ppm, less than about 50ppm or less than about 20ppm of water.

[00133] In embodiments where the chlorinated C3-6 alkane of interest is 1,1,1,3-tetrachloropropane, the following are examples of specific impurities that are minimized, not produced and/or removed in the processes of the present invention: trichloromethane , 1,2-dichloroethane, 1-chlorobutane, 1,1,1-trichloropropane, tetrachloroethene, 1,1,3-trichloroprop-1-ene, 1,1,1,3,3-pentachloropropane, 1,1,1 ,2,3-pentachloropropane, hexachloroethane, 1,1,1,5-tetrachloropentane, 1,3,3,5-tetrachloropentane, tributylphosphate, chlorinated alkanol and chlorinated alkanoyl compounds.

Thus, in embodiments of the present invention, 1,1,1,3-tetrachloropropane product comprises about 500ppm or less, about 200ppm or less, about 100ppm or less, about 50ppm or less, about 20ppm or less or about 10ppm or less of one or more of these compounds.

[00135] For the avoidance of doubt, when the purity of a composition or material is given by percentage or ppm, unless otherwise stated, this is a percentage/ppm by weight.

[00136] As mentioned previously, the prior art does not disclose or teach processes to produce chlorinated alkanes having such a high degree of purity, in which an overall range of possible impurities is managed. Thus, in accordance with other aspects of the present invention, high purity chlorinated alkane compositions are provided as specified above. BRIEF DESCRIPTION OF DRAWINGS

EXAMPLES

[00137] The present invention is now further illustrated in the following examples.

EXAMPLE 1 - DEMONSTRATION OF CATALYTIC CAPACITY OF RECOVERED CATALYST USING AN AQUEOUS TREATMENT

[00138] Ethene and carbon tetrachloride were reacted to produce 1,1,1,3-tetrachloropropane in the presence of a catalyst which either i) was recovered from a reaction mixture using conventional distillation techniques, or ii) recovered to from a reaction mixture using the aqueous treatment step of the invention for catalyst described herein. The reaction mixture additionally comprised 1,1,1,3-tetrachloropropane (present in the recycle stream) and tetrachloropentane (a chlorinated alkane impurity commonly formed as a by-product in the presence of telomerization reactions between carbon tetrachloride and ethene) .

[00139] These test examples show that using the aqueous treatment step to recover catalyst, catalyst performance is significantly higher when compared to catalyst recovered using conventional distillation techniques.

[00140] For brevity, the following terms are used in the examples specified below: TeCM: tetrachloromethane. TeCPa: 1,1,1,3-tetrachloropropane TeCPna: tetrachloropentane, Bu3PO4: tributylphosphate

[00141] Gas chromatography was used to monitor the progress of the reaction.

Batch arrangement

[00142] A stainless steel autoclave with a volume of 405 ml, equipped with an agitator, a THERMOWELL for temperature measurement and a sampling tube (with valve) was filled with the reaction mixture described below and closed. Heating was provided by means of an oil bath placed on a magnetic stirrer (heating). Ethene was fed into a copper capillary tube from a 10 L cylinder placed on a balance. The gaseous atmosphere in the autoclave was replaced by washing with ethylene. After pressurizing with ethylene at 5 bar, the autoclave was heated to 105°C, then the ethylene supply to the autoclave was opened. The ethylene supply was manually controlled for the first ten minutes (to maintain the reaction temperature at 112°C), and then maintained at a constant pressure of 9 bar. The reaction was allowed to react for a defined period of time. Then, the reactor was cooled and the reaction mixture was removed after opening the depressurized reactor.

Comparative Examples 1-1 and 1-3 and Examples 1-2, 1-4 and 1-5

[00143] In the first example, the distillation residue was used directly as a recycled catalyst (Comparative Example 1-1). In the second example, the distillation residue was extracted with 5% hydrochloric acid and a filtered organic fraction was used as a catalyst (Example 1-2).

Comparative Example 1-1

[00144] 90.1 g of a distillation residue comprising 63.7%TeCPa, 22.8% TeCPna and 7.49% Bu3PO4 were mixed with 400 g of TeCM. The mixture was then introduced into the autoclave where 5.0 g of iron was added. After washing with ethene, the mixture was heated in the autoclave to 110°C. At this temperature and pressure of 9 bar of ethylene, the reaction mixture was allowed to react for 4.5 hours. The first sample was taken after 3 hours. The residual TeCM concentration at the end of the experiment was 19.7% (33.0% after 3 hours).

Example 1-2

[00145] 90.1 g of a distillation residue comprising 63.7%TeCPa, 22.8% TeCPna and 7.49% Bu3PO4 were extracted with 370 g of 5% HCl. A bottom organic layer was filtered and mixed with 400 g TeCM. The mixture was then introduced into the autoclave where 5.0 g of iron was added. After washing with ethene, the mixture was heated in the autoclave to 110°C. At this temperature and pressure of 9 bar of ethylene, the reaction mixture was allowed to react for 4.5 hours. The first sample was taken after 3 hours. The residual TeCM concentration at the end of the experiment was 5.5% (24.6% after 3 hours).

Comparative Example 1-3

[00146] Comparative Example 1-3 was carried out using conditions identical to those employed in Comparative Example 1-1, except that different concentrations of tetrachloromethane and tributylphosphate were used.

Examples 1-4 and 1-5

Examples 1-4 and 1-5 were carried out using conditions identical to those used in Example 1-2, except that different concentrations of tetrachloromethane and tributylphosphate were used.

[00148] The results of Comparative Example 1-1 and Example 1-2 and Comparative Example 1-3 and Examples 1-4 and 1-5 are illustrated in the following table. As can be seen, the percentage of tetrachloromethane that has been converted to 1,1,1,3-tetrachloropropane is significantly higher in Examples 1-2, 1-4 and 1-5 than in Comparative Examples 1-1 and 1-3 , demonstrating that the performance of an aqueous treatment step, when recovering the catalyst, has a profound positive effect on the system. This is due to the high viability of the catalyst recovered from the distillate residue and also potentially due to the removal of impurities (eg oxygenated impurities) from the reaction mixture that could otherwise slow down the reaction.

Continuous Disposition:

[00149] The same stainless steel autoclave as described above for the batch experiments was used as a continuous stirred-flow reactor. The reactor was initially filled with approximately 455 g of reaction mixture. After pressurizing with ethylene at 5 bar, the autoclave was heated to 105 °C, then the supply of ethylene to the autoclave was opened, with continuous feed of raw material and continuous removal of the initiated reaction mixture.

[00150] Raw material solution with dissolved catalyst was fed into the autoclave from a stainless steel tank. The tank was placed above the reactor and thus a pump was not used to power the reactor. Reactor and tank were under an atmosphere of ethylene distributed by copper capillaries from the cylinder, with conditions in the cylinder selected to prevent the reaction from starting. Sampling of the reaction mixture was performed by sampling the tube every five minutes. To monitor the course of the reaction, the vessel with the charge of feed and dissolved catalyst, the ethylene cylinder and the withdrawn reaction mixture were weighed. The reaction mixture was always collected for one hour and then the collection vessel was replaced.

Comparative Example 1-6 and 1-8 and Examples 1-7 and 1-9

[00151] Continuous experiments comparing the activity of the recycled catalyst (ie, a distillation residue) were conducted with and without carrying out an aqueous treatment step. In the first case, the distillation residue was directly used as a recycled catalyst (Comparative Example 1-6). In the latter cases, the reaction mixture, after aqueous treatment of the distillation residue with 5% HCl, was used as a raw material containing recycled catalyst (Examples 1-4 and 1-5).

Comparative Example 1-6

[00152] 587.5 g of the distillation residue comprising 63.7%TeCPa, 22.8% TeCPna and 7.49% Bu3PO4 were mixed with 2200 g of TeCM. This mixture comprised 78.7% TeCM, 11.8% TeCPa, 5.8% TeCPna and was used as a feed stream in the continuous arrangement. The reaction vessel consisting of an autoclave was filled with reaction mixture and 8 g of fresh iron. The reaction was carried out at 110°C with an ethene pressure of 9 bar. Residence time was 2.7 hours. During the reaction, the amount of TeCM reacted was in the range of 75 - 76%.

Example 1-7

[00153] 587.5 g of the distillation residue comprising 63.7%TeCPa, 22.8% TeCPna, 7.49% Bu3PO4 were added dropwise over 1.5 hours in boiling 1001.5 g of 5% HCl . This mixture was then removed. From the top product, an organic phase was collected and an aqueous phase was returned as a reflux. Distillation was finished after one hour when all the distillation residue was added. The residue, after removal, was diluted with 200 g of TeCM and then separated in a separatory funnel. A bottom organic phase was filtered and together with distilled residue was mixed with 2000 g of TeCM. This mixture consisted of 81.2% TeCM, 10.8% TeCPa and 5.3% TeCPna. It was used as a supply current for the continuous arrangement of the experiment. The reaction vessel (autoclave) was filled with the reaction mixture from above and 8 g of fresh iron. The reaction was carried out at 110°C and an ethylene pressure of 9 bar. Residence time was 2.7 hours/flow rate. During the reaction time, the amount of TeCM reacted was in the range between 83 - 85%.

Comparative Example 1-8

[00154] Comparative Example 1-8 was carried out using conditions identical to those employed in Comparative Example 1-6, except that different concentrations of tetrachloromethane and tributylphosphate were used.

Example 1-9

[00155] Example 1-9 was carried out using conditions identical to those employed in Example 1-7, except that different concentrations of tetrachloromethane and tributylphosphate were used.

EXAMPLE 2 - PREPARATION OF HIGH PURITY 1,1,1,3-TETRACHLOROPROPAN

[00156] High purity 1,1,1,3-tetrachloropropane can be obtained according to a process of the present invention involving an alkylation step (Figure 1), a first distillation step (Figure 2), a recovery step of the aqueous catalyst (Figure 3) and a second distillation step (Figure 4). However, it will be appreciated that not all of these steps are necessary to obtain high purity C3-6 alkane according to the processes of the present invention.

[00157] In the alkylation step shown in Figure 1, ethylene and particulate iron are fed via lines 1 and 2 into a continuously stirred tank reactor 3. The ethylene is introduced into the continuously stirred tank reactor 3 in gaseous form via a tube of immersion equipped with a nozzle. A controlled feed of particulate iron is fed into the continuously stirred tank reactor 3.

[00158] Particulate iron is fed intermittently into the continuously stirred tank reactor 3 using a controlled feed. The ongoing addition of particulate iron is employed because, as the alkylation reaction proceeds, particulate iron dissolves in the reaction mixture. It was found that optimal results are obtained maintaining the presence of particulate iron in the reaction mixture, in this example, with the addition of 1 to 2% by weight of the reaction mixture in the primary alkylation zone. This results in the reaction mixture extracted from the primary alkylation zone having a dissolved iron content of 0.2 to 0.3% by weight of the reaction mixture.

[00159] Carbon tetrachloride is fed into the continuously stirred tank reactor 3 via line 12 in liquid form. In the illustrated embodiment, the carbon tetrachloride stream is used to capture gaseous ethylene extracted from the reaction mixture. However, the use of carbon tetrachloride in this way is not essential to the present invention; a fresh carbon tetrachloride feed as the sole or main source of carbon tetrachloride can be fed into reactor 3.

[00160] Tributylphosphate/ferric chloride catalyst is also fed into the continuously stirred tank reactor 3 via line 12. The tributylphosphate present in this stream is partially obtained from the aqueous treatment process illustrated in Figure 3 (and discussed in more detail below) , with the rest being supplied as fresh tributylphosphate added to the system. On-line stream 12 additionally comprises a haloalkane extracting agent.

[00161] In the illustrated embodiment, a single primary alkylation zone is employed, located in the continuously stirred tank reactor 3. Of course, if necessary, a plurality of primary alkylation zones can be employed, for example, in one or more reactors. of continuously agitated tanks, which could be operated in parallel and/or in series.

The primary alkylation zone is operated under superatmospheric pressure (5 to 8 bar gauge) and elevated temperature (105°C to 110°C) and for a residence time of 100-120 minutes. These conditions are selected to cause carbon tetrachloride and ethene to form 1,1,1,3-tetrachloropropane in an alkylation reaction. However, it has been found that the total conversion of carbon tetrachloride to 1,1,1,3-tetrachloropropane is undesirable as it also results in the formation of unwanted impurities. Thus, the level of conversion of carbon tetrachloride to the chlorinated C3-6 alkane of interest is controlled and, in this embodiment of the invention, it is not allowed to proceed beyond 95%. Controlling the progress of the alkylation reaction is partially achieved by using reaction conditions that do not favor the full conversion of carbon tetrachloride to 1,1,1,3-tetrachloropropane, by controlling the residence time of the reaction mixture in the continuously stirred tank reactor.

[00163] Reaction mixture comprising i) unreacted carbon tetrachloride and ethene, ii) 1,1,1,3-tetrachloropropane (the chlorinated C3-6 alkane of interest in this embodiment) and iii) tributylphosphate/iron chloride catalyst is extracted from the primary alkylation zone (the continuously stirred tank reactor 3) and fed into a buffer flow reactor 4 (in which the main alkylation zone is located).

[00164] The reaction mixture is extracted so that the particulate iron catalyst present in the primary alkylation zone 3 is not extracted and thus the reaction mixture is substantially free of particulate material. Furthermore, in the illustrated embodiment, no additional catalyst is added in plug-flow reactor 4, although plug-flow reactor 4 can be provided with a bed of catalyst. Additionally, no more ethylene is added to the buffer 4 flow reactor.

[00165] In the illustrated embodiment, the operating pressure in the main alkylation zone 4 is the same as in the primary alkylation zone 3. The residence time of the reaction mixture is about 30 minutes, which, in the illustrated embodiment, is sufficient to result in substantially all of the ethylene present being used in the reaction. Of course, it should be understood that for different reactor types and operating conditions, different residence times can be optimal.

[00166] When the determined optimal residence time of the reaction mixture in the main alkylation zone has been reached, the reaction mixture is extracted from there via line 5, while being maintained at elevated pressure and temperature and fed into flash evaporation vessel 6 In this vessel, the extracted reaction mixture is subjected to depressurization at atmospheric pressure. This pressure drop causes the ethylene present in the reaction mixture to evaporate. The 1,1,1,3-tetrachloropropane-rich mixture, now substantially without ethylene present, is extracted from the FLASH vessel via line 7 and subjected to the distillation step shown in Figure 2, and discussed in more detail below.

[00167] The evaporated ethylene is extracted from the FLASH vessel 6 via line 8 and fed through a condenser 9. The ethylene is then fed via line 10 to the absorption column 11 where it is contacted with a stream of carbon tetrachloride and tributylphosphate/iron chloride catalyst recovered from the reaction mixture in the aqueous treatment step shown in Figure 3, and discussed in greater detail below. The recovered catalyst/carbon tetrachloride stream 13 is passed through a cooler 14 and then fed via line 15 to absorption column 11.

[00168] The cooled carbon tetrachloride/catalyst flow through the absorption column 11 has the effect of trapping the ethylene therein. The obtained liquid stream from carbon tetrachloride/catalyst/ethene is then fed back to the continuously stirred tank reactor 3.

[00169] As is evident from Figure 1, the illustrated embodiment includes an ethylene recycling circuit which is advantageous for several reasons. First, an almost total utilization of the ethylene is achieved and thus the amount of ethylene lost from the system is very low. Additionally, energy requirements of the components of the ethylene recycling system are also low. Furthermore, the amount of ethylene lost from the system is also very low, meaning that the environmental load is reduced.

[00170] Returning now to Figure 2, the 1,1,1,3-tetrachloropropane-rich mixture extracted from the FLASH vessel, shown with reference number 6 in Figure 1, is fed via line 101 into a distillation boiler by batch 102, which is operated in communication with a vacuum distillation column 104. The distillation boiler is operated at a temperature of 90°C to 95°C. Chloroalkanes present in the mixture fed to reboiler 102 are evaporated and separated using distillation column 104 (and downstream condenser 106 and reflux divider 108) into light end products stream 110.1, carbon tetrachloride stream 110.2, tetrachloroethene stream 110.3 and purified 1,1,1,3-tetrachloropropane product stream 110.4.

[00171] The light and standard end products of tetrachloroethene 110.1, 110.3 can be used in the production of carbon tetrachloride, advantageously minimizing the production of waste products. This can be achieved through the use of a high temperature chlorinolysis process.

[00172] The carbon tetrachloride stream 110.2 is recycled back to the continuously stirred tank reactor 103. The purified 1,1,1,3-tetrachloropropane product stream is extracted from the system and can be stored for shipment or used in downstream processes requiring pure 1,1,1,3-tetrachloropropane as a starting material.

[00173] A mixture rich in 1,1,1,3-tetrachloropropane which also comprises catalyst is extracted as a residue from reboiler 102 via line 103 and is subjected to the catalyst recovery step shown in Figure 3.

[00174] In this step, the mixture rich in 1,1,1,3-tetrachloropropane is fed into a 204 batch distillation boiler via line 202, together with a solution of weak hydrochloric acid (1-5%) via line 201 .

[00175] Advantageously, the water present in the acidic solution deactivates the catalyst system and protects it from thermal damage. This allows the catalyst system to be recovered from the 1,1,1,3-tetrachloropropane rich mixture and can be easily reactivated, after recovery and reused in the alkylation process without any significant loss in catalytic activity.

[00176] The batch distillation boiler is operated at a temperature of about 100°C to create a gas mixture comprising 1,1,1,3-tetrachloropropane and water vapor.

[00177] The gas mixture produced in the boiler 204 is then subjected to steam distillation (or steam removal) of crude 1,1,1,3-tetrachloropropane in column 210, which is coupled to the boiler 204. 1,1,3-tetrachloropropane is extracted from distillation column 210 via line 211, condensed with a condenser 212, fed via line 213 to a liquid-liquid (reflux) separator 214. Water from the gas mixture is fed back to the distillation column 210 via line 215, and a portion is withdrawn via line 216 for another distillation step, shown in greater detail in Figure 4 and discussed in greater detail below.

[00178] The operating temperature of the boiler 204 is then reduced to stop the removal of steam, resulting in the condensation of water vapor present in it. This results in the formation of a two-phase mixture containing an aqueous phase and an organic phase containing the catalyst system, which has not been subjected to steam removal. To facilitate extraction of the organic phase, a haloalkane extracting agent (in this case 1,1,1,3-tetrachloropropane) is added to boiler 204, via line 203, to increase the volume of this phase.

[00179] Extraction of the organic phase from the biphasic mixture is achieved by sequentially extracting the phases from the reboiler 204 via line 205. The organic phase is extracted from the reboiler 204 via line 205 and is filtered 206. A filter cake is removed of filter 206 via line 207. The organic phase is extracted via line 208 and, in this modality, fed back to the primary alkylation zone, as shown in Figure 1, specifically via line 13 in Figure 1. The aqueous phase is extracted via line 205, filtered 206 and eliminated via line 209.

[00180] The removed crude 1,1,1,3-tetrachloropropane product is subjected to another distillation step shown in Figure 4. In this step, the crude product is fed into a distillation reboiler 302 via line 301. The reboiler 302 is in communication with distillation column 304. Evaporated chlorinated organic compounds present in the crude 1,1,1,3-tetrachloropropane are separated in distillation column 304 (and related downstream apparatus, condenser 306 and reflux divider 308) at a 1,1,1,3-tetrachloropropane 310.1 product stream and a chlorinated pentane/pentene 310.2 stream.

[00181] The chlorinated pentane/pentene 310.2 stream can be used in the production of carbon tetrachloride, advantageously minimizing the production of waste. This can be achieved through the use of a high temperature chlorinolysis process.

[00182] The purified 1,1,1,3-tetrachloropropane 310.1 product stream is extracted from the system and can be combined with the main product stream (identified with reference number 110.4 in Figure 2). The product can be stored for shipment or used in downstream processes requiring pure 1,1,1,3-tetrachloropropane as starting material.

[00183] The heavy end product residue extracted from the reboiler 302 via line 303 is either discarded or further processed.

[00184] Using the apparatus and process conditions outlined above, 2635 kg of carbon tetrachloride (CTC, 99.97% purity) were processed continuously with an average hourly load of 78.2 kg/h to produce 1.1 ,1,3-tetrachloropropene (1113TeCPa). The basic parameters of the described process carried out according to Example 2 are as follows.

[00185] The complete impurity profile of the purified product of the modality described above is presented in the following table. Please note that the figures are given as a weighted average of the profiles for the product obtained in line 110.4 in Figure 2 and line 310.1 in Figure 4.

EXAMPLE 3: EFFECT ON THE SELECTIVITY OF THE MOLAR RATIO OF THE STARTING MATERIAL: PRODUCT IN REACTION MIXTURE.

[00186] These examples were carried out using the equipment and techniques outlined above in "Continuous Device" in Example 1, unless otherwise noted. The molar ratio of the chlorinated C3-6 alkane product (in this case 1,1,1,3-tetrachloropropane): carbon tetrachloride in the reaction mixture was controlled to different levels, mainly by the residence time of the reaction mixture in the zone of alkylation. The temperature was maintained at 110°C and the pressure was maintained at 9 bar. The selectivities for the product of interest are presented in the following table:

[00187] As can be seen from this example, when the molar ratio of product:starting material exceeds 95:5 when the process is operated on a continuous basis, there is a notable reduction in selectivity relative to the product of interest.

EXAMPLE 4: EFFECT ON THE SELECTIVITY OF THE MOLAR RATIO OF STARTING MATERIAL: PRODUCT IN REACTION MIXTURE.

[00188] These examples were performed using the equipment and techniques as illustrated in Figure 1, with reference to the text accompanying Example 2 above, unless otherwise specified. The molar ratio of the chlorinated C3-6 alkane product (in this case 1,1,1,3-tetrachloropropane): carbon tetrachloride in the reaction mixture was controlled at different levels, mainly by controlling the feed rate of the starting material of ethylene. The temperature was constantly 110°C. The selectivities for the product of interest are reported in the following table:

[00189] As can be seen from this example, when the molar ratio of product:starting material exceeds 95:5 when the process is operated on a continuous basis, there is a notable reduction in selectivity relative to the product of interest. 5: PURITY EFFECTS OF THE FOOD LOAD

[00190] These examples were performed using the equipment and techniques as illustrated in Figure 2, with reference to the text accompanying Example 2 above, unless otherwise indicated. Experiment 5-1 is the current taken from current 110.4 in Figure 2. Experiments 5- 2 - 5 to 5 are alternative examples, obtained using the same apparatus and techniques, but employing feed loads of different purity. The data below demonstrate that, although a lower purity feed load was used in experiments 5-2 to 5-5, this advantageously does not significantly impact the purity of the product when obtained from the processes of the present invention. .

EXAMPLE 6: COMBINATION OF CSTR AND BUFFER FLOW

[00191] These examples were performed using the equipment and techniques as illustrated in Figure 1, with reference to the text accompanying Example 2 above, unless otherwise specified. The reaction efficiency in the second buffer flow reactor (reference number 4 in Figure 1) was evaluated. Two experiments were conducted with a different amount of ethylene dissolved at the inlet of the plug flow reactor which was operated at the same temperature, 110°C, as the main CSTR reactor (reference number 3 in Figure 1). The results are shown in the following table:

[00192] As can be seen from this example, there is an ethylene conversion between 75 - 93% in the plug flow reactor. Thus, if a plug-flow reactor is employed, more efficient use of ethylene occurs in the reaction section. The series continuous flow reactor allows the CSTR reactor to be operated at an optimal pressure without the need for complex and uneconomical ethylene recovery processes. The plug flow reactor therefore controls the use of ethylene in an efficient closed loop.

EXAMPLE 7: PROBLEMATIC DEGRADATION OF CATALYST LIGAND DURING CONVENTIONAL DISTILLATION.

[00193] Fractional distillation equipment consisting of a two liter glass distillation flask, with four necks, equipped with condenser, thermometer, heating bath and vacuum pump system was configured. The distillation flask was initially filled with 1976 grams of reaction mixture obtained using the apparatus and techniques illustrated in Figure 1 and explained in the text accompanying Example 2 above.

[00194] During the distillation, the pressure was gradually reduced from an initial pressure of 100 mmHg to a final pressure of 6 mmHg. During this period, 1792 grams of distillate (in different fractions) were extracted. During distillation, there was visible formation of HCl gas and more chlorobutane (the breakdown product of tributylphosphate binder) was also formed in significant amounts, notably between 1 to 19% for distillate fractions. After these observations were made, the distillation was stopped, distillation residue was weighed and analyzed and it had, as verified, a tetrachloropropane content of 16%. It was no longer possible to continue the distillation without significant degradation of the tributylphosphate binder.

Claims (22)

1. Process for producing high quality 1,1,1,3-tetrachloropropane, characterized in that it comprises providing a reaction mixture comprising ethylene and carbon tetrachloride and an organic phosphate catalyst in a main alkylation zone to produce 1,1,1,3-tetrachloropropane in the reaction mixture, and extracting a portion of the reaction mixture from the main alkylation zone, wherein the main alkylation zone is operated continuously and conversion to the reaction mixture in the main alkylation zone is kept below 95 by distilling off a mixture of 1,1,1,3-tetrachloropropane and the reaction mixture catalyst; and said mixture is fed back into the reaction mixture provided in the main alkylation zone; and the reaction mixture extracted from the main alkylation zone is subjected to an aqueous treatment step in which the reaction mixture is contacted with an aqueous medium in an aqueous treatment zone, a biphasic mixture is formed and an organic phase comprising catalyst is extracted from the biphasic mixture. 2. Process according to claim 1, characterized in that the organic binder of the catalyst is an alkyl phosphate, for example triethyl phosphate and/or tributyl phosphate. 3. Process according to claim 1 or 2, characterized in that the main alkylation zone is operated at a temperature of 30°C to 160°C. 4. Process according to any one of claims 1 to 3, characterized in that the main alkylation zone is operated at a temperature of 80°C to 120°C. 5. Process according to any one of claims 1 to 4, characterized in that the reaction mixture is formed in the main alkylation zone. 6. Process according to any one of claims 1 to 5, characterized in that ethylene and carbon tetrachloride are in contact in a primary alkylation zone to form the reaction mixture, the reaction mixture is then extracted from the primary alkylation zone and fed into the main alkylation zone, wherein the ratio of 1,1,1,3-tetrachloropropane:carbon tetrachloride present in the reaction mixture extracted from the main alkylation zone is greater than the ratio of 1, 1,1,3-tetrachloropropane: carbon tetrachloride present in the reaction mixture taken from the primary alkylation zone. 7. Process according to claim 6, characterized in that the main alkylation zone is operated at the same or a different pressure than that of the primary alkylation zone. 8. Process according to claim 6 or 7, characterized in that the primary alkylation zone is operated in a continuous process. 9. Process according to any one of claims 6 to 8, characterized in that no alkene or solid metal catalyst is fed into the main alkylation zone other than that present in the reaction mixture fed into the main alkylation zone. 10. Process according to any one of claims 6 to 9, characterized in that the reaction mixture taken from the primary alkylation zone and fed into the main alkylation zone is substantially free of solid metal catalyst. 11. Process according to claim 1, characterized in that the reaction mixture extracted from the main alkylation zone additionally comprises ethylene and the reaction mixture is subjected to a desalting step in which at least 50% or more by weight of the ethylene present in the reaction mixture is extracted from it and at least 50% of the extracted ethylene is fed back into the reaction mixture supplied to the main alkylation zone 12. Process according to claim 11, characterized in that the desalting step comprises feeding the reaction mixture extracted from the main alkylation zone to a distillation zone, in which ethylene is distilled from the reaction mixture. 13. Process according to claim 12, characterized in that the alkene distilled from the reaction mixture is obtained in a stream rich in ethylene. 14. Process according to claim 12 or 13, characterized in that the distillation zone is an evaporation zone in which ethylene is evaporated from the reaction mixture. 15. Process according to any one of claims 1 to 14, characterized in that about 30% to about 85% by weight of 1,1,1,3-tetrachloropropane present in the reaction mixture extracted from the alkylation zone principal is removed from the reaction mixture prior to the aqueous work-up step, optionally by distillation. 16. Process according to claim 15, characterized in that the aqueous medium comprises dilute acid, optionally dilute hydrochloric acid. 17. Process according to claim 15, characterized in that most of the 1,1,1,3-tetrachloropropane present in the reaction mixture fed into the aqueous treatment zone is extracted from the mixture formed in the aqueous treatment zone, optionally by distillation. 18. Process according to claim 15, characterized in that it additionally comprises the step of feeding carbon tetrachloride and/or 1,1,1,3-tetrachloropropane into the aqueous treatment zone. 19. Process according to any one of claims 1 to 18, characterized in that the two-phase mixture is formed in the aqueous treatment zone. 20. Process according to claim 15, characterized in that the organic phase is extracted from the biphasic mixture by sequential phase separation. 21. Process according to claim 15, characterized in that steam is fed into the aqueous treatment zone and/or is formed IN SITU by boiling water present in the aqueous treatment zone to produce a gas mixture comprising 1,1,1 ,3-tetrachloropropane and water vapor from which 1,1,1,3-tetrachloropropane can be distilled. 22. Process according to any one of claims 1 to 21, characterized in that the product of 1,1,1,3-tetrachloropropane has a purity of 99.0% or more, 99.5% or more, 99 ,7% or more, 99.8% or more, or 99.9% or more and comprises: less than 2000ppm, less than 1000ppm, less than 500ppm, less than 200ppm or less than 100ppm of alkane impurities chlorinated (ie, chlorinated alkane compounds other than 1,1,1,3-tetrachloropropane), less than 2000ppm, less than 1000ppm, less than 500ppm, less than 200ppm or less than 100ppm of compounds of chlorinated alkene, less than 2000ppm, less than 1000ppm, less than 500ppm, less than 200ppm or less than 100ppm of oxygenated organic compounds,less than 2000ppm, less than 1000ppm, less than 500ppm, less than than 200ppm or less than 100ppm brominated compounds, less than 1000ppm, less than 500ppm, less than 200ppm, less than 100ppm, less than 50ppm or less than 20p pm of water, less than 500ppm, less than 200ppm, less than 100ppm, less than 50ppm or less than 20ppm of metallic catalyst, and/or less than 500ppm, less than 200ppm, less than 100ppm, less than 50ppm or less than 20ppm catalyst promoter.

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